DESCRIPTION: The goals of this proposal are to understand in more detail the trafficking of lymphocytes in HIV infection. One aim focuses on patterns of lymph node (LN) involvement with HIV during the disease course using PET scanning to identify LN sites of activation (a presumed surrogate for sites of infection). This study will longitudinally follow newly infected and chronically subjects begun on HAART for about 18 mo and will translate to humans previous primate studies. The second aim moves to the cellular level to study the chemotactic properties of CXCR4 and CCR5 tropic HIV gp120 or whole virions on different subsets of resting or activated T lymphocytes and monocytes.